Recent advances in digital signal processing techniques and, in particular, advances in digital compression techniques, have led to a plethora of proposals for providing new digital services to a subscribers home via existing telephone and coaxial networks. For example, it has been proposed to provide hundreds of cable television channels to subscribers by compressing digital video, transmitting the compressed digital video over conventional coaxial cable television cables, and then decompressing the video at the subscriber's set top terminal. Another proposed application of this technology is a movie-on-demand system in which a subscriber communicates directly to the video service provider via telephone lines to request a particular video program from a video library and the requested video program is routed to the subscriber's home via telephone lines or via coaxial television cables for immediate viewing.
However, these present movie-on-demand video systems are not truly interactive systems wherein a subscriber can selectively access a large audio, video or data library and control the presentation of the selected information on a real time basis, as when a video program is played back using the viewer's conventional video cassette recorder. Most of the presently available systems have a simple control interface that permits the subscriber to merely order information without any further control of the presentation of the information. Typically the set top terminals in these forms of systems merely demodulate the signal from the cable network and present them to the viewer on the viewer's conventional television. Control information from the set top terminal to the service provider is typically carried by the telephone network. As such, only rudimentary commands are permitted, otherwise a dedicated telephone line would be necessary.
Therefore, there is a need in the art for a set top terminal that is capable of interacting with an interactive information distribution system to provide real time interaction with the services provided by the service provider.